JP2009186034A - Economizer - Google Patents

Abstract

An economizer used in a multistage compression refrigeration apparatus is provided at low cost.
An economizer (24) is provided in a multistage compression refrigeration apparatus having a refrigerant circuit in which a multistage compressor, a condenser, a multistage expansion means, and an evaporator are sequentially connected. In addition, the economizer (24) introduces a gas refrigerant in the middle of the multistage compressor, an introduction part (24d) for introducing the refrigerant in the refrigerant circuit, a liquid outlet part (24b) for leading the liquid refrigerant to the evaporator A tank (24a) formed with a gas outlet part (24c) and an expansion valve constituting a part of the multistage expansion means, attached to the liquid outlet part (24b), and in the tank (24a) And a float expansion valve (25) whose throttle amount is adjusted according to the liquid level of the liquid refrigerant. A plurality of liquid outlets (24b) and a plurality of float expansion valves (25) are provided.
[Selection] Figure 2

Description

  The present invention relates to an economizer used in a multistage compression refrigeration apparatus.

  2. Description of the Related Art Conventionally, a two-stage compression refrigeration apparatus including a refrigerant circuit in which a two-stage compressor, a condenser, a two-stage expansion unit, and an evaporator are sequentially connected has been used. Further, in a two-stage compression refrigeration system, an economizer that separates a gas refrigerant from a gas-liquid two-phase refrigerant and guides it to the middle of a two-stage turbo compressor is used to perform an operation with a high coefficient of performance (COP). (For example, refer to Patent Document 1).

The economizer described in FIG. 2 of Patent Document 1 includes an introduction part for introducing a refrigerant, a gas outlet part for introducing the separated gas refrigerant to the two-stage compressor, and a liquid outlet for introducing the separated liquid refrigerant to the evaporator. It is comprised by the tank in which the part was formed. The tank is provided with a float expansion valve that is attached to the liquid outlet and adjusts the amount of throttling according to the liquid level of the liquid refrigerant.
JP-A-11-344265

  However, in the economizer, only one liquid outlet is provided, and a large amount of liquid refrigerant flows out from one liquid outlet. For this reason, there is a problem that the float expansion valve must be a large one and the cost increases. In particular, in an economizer used for a large-capacity multi-stage turbo refrigerator, since the differential pressure before and after the float expansion valve is small, a larger float expansion valve is required, so the problem is serious.

  This invention is made | formed in view of this point, The place made into the objective is to provide the economizer used for a multistage compression refrigerating apparatus at low cost.

  The present invention relates to a multistage compressor comprising a refrigerant circuit (20) in which a multistage compressor (21), a condenser (22), multistage expansion means (23, 25), and an evaporator (26) are sequentially connected. An economizer provided in an air-conditioning refrigeration system (1) for separating gas-liquid two-phase refrigerant into gas-liquid separation, guiding gas refrigerant to the middle of the multistage compressor (21), and guiding liquid refrigerant to the evaporator (26) An introduction part (24d) for introducing refrigerant in the refrigerant circuit (20), a liquid outlet part (24b) for introducing liquid refrigerant to the evaporator (26), and the multistage compressor (21 ) In which a gas outlet (24c) for introducing a gas refrigerant is formed, and an expansion valve constituting a part of the multistage expansion means (23, 25), A float expansion valve (25) attached to the liquid outlet part (24b), the throttle amount of which is adjusted according to the liquid level of the liquid refrigerant in the tank (24a) A plurality of the liquid outlet part (24b) and the float expansion valve (25) are provided.

Furthermore, the tank (24a) is a tank that is long in the horizontal direction, and the introduction part (24d) is formed at the center in the longitudinal direction of the tank (24a), and the liquid outlet part (24b) and the float expansion valve (25) is arranged on both sides of the introduction part (24d) in the longitudinal direction of the tank (24a).

In addition, the inside of the tank (24a) is located between the introduction part (24d), the liquid outlet part (24b) and the float expansion valve (25), and crosses the tank (24a). Extending in the surface direction, the tank (24a) into a space in the center where the introduction part (24d) is arranged and a space on the liquid outlet part side where the liquid outlet part (24b) is arranged, A baffle plate (24e, 24f) is provided that constitutes a partition wall that partitions the refrigerant so that the refrigerant flows from the space in the central portion to the space on the liquid outlet portion side.

In addition, two gas outlet portions (24c) are provided, and each gas outlet portion (24c) is disposed in a space on the liquid outlet portion side in the longitudinal direction of the tank (24a).

In the present invention, the liquid refrigerant flows out from the tank (24a) through the plurality of liquid outlet portions (24b), and the outflow amount of the liquid refrigerant is controlled by the plurality of float expansion valves (25). The Therefore, the control amount required for each float expansion valve (25) is smaller than when the outflow amount is controlled by one float expansion valve (25). Therefore, Ru can be used a small float expansion valve (25).

The float expansion valve (25) is disposed on both sides of the introduction part (24d) in the longitudinal direction of the tank (24a). Thus, each float expansion valve (25) is Ru are arranged in a gap between introduction part (24d).

The gas-liquid two-phase refrigerant introduced from the introduction part (24d) collides with the baffle plates (24e, 24f) when flowing to the liquid outlet part (24b) and the float expansion valve (25) side. The gas-liquid is separated. Further, since the baffle plates (24e, 24f) are provided between the introduction part (24d) and the float expansion valve (25), the refrigerant introduced from the introduction part (24d) is used as the float expansion valve (25). Ru is avoided blowing take directly.

Further , the gas refrigerant is not sucked in intensively from one gas outlet (24c), but is distributed and sucked into two gas outlets (24c). Therefore, compared with the case where only one gas outlet part (24c) is provided, the force at which each gas outlet part (24c) sucks the gas refrigerant is halved. Thereby, the rise in the liquid refrigerant level caused by the suction of the gas refrigerant in the vicinity of the gas outlet (24c) is suppressed. As a result, a so-called liquid return in which a part of the liquid refrigerant is sucked from the gas outlet (24c) to the multistage compressor (21) side is avoided.

In a second aspect based on the first aspect, the liquid outlet part (24b) and the float expansion valve (25) are provided one by one in the space on the liquid outlet part side.

In the second invention, since two liquid outlet portions (24b) are provided, the outflow amount of the liquid refrigerant flowing out from the tank (24a) is controlled by the two float expansion valves (25). Thereby, since the control amount calculated | required by one float expansion valve (25) becomes a half of the past, a float expansion valve (25) smaller than before can be used.

  As described above, according to the present invention, since the small float expansion valve (25) can be used, the unit price of the float expansion valve (25) can be significantly reduced, and the cost of the entire economizer (24) can be reduced. Can be reduced.

In addition, according to the present invention, since a plurality of float expansion valves (25) are provided, even if one float expansion valve (25) does not operate due to a malfunction, the other float expansion valve (25) causes liquid refrigerant to flow. Pressure reduction and liquid level control in the economizer (24) can be performed. Therefore, even if a malfunction occurs in the float expansion valve (25), the operation of the multistage compression refrigeration system (1) provided with the economizer (24) can be operated by partial load operation without immediately stopping the operation. Ru can be continued.

Moreover, since each float expansion valve (25) is arrange | positioned at intervals with an introducing | transducing part (24d), it avoids that the refrigerant | coolant introduced from the introducing | transducing part (24d) sprays on the float expansion valve (25). Can do. As a result, it is possible to prevent the introduced refrigerant from affecting the operation of the float expansion valve (25).

Further, Ji Yamaban (24e, 24f) by providing the refrigerant is the baffles in the gas-liquid two-phase state (24e, 24f) while being gas-liquid separated by impinging on, introducing portion (24d) It is possible to prevent the refrigerant introduced from the above from directly blowing on the float expansion valve (25) and affecting the operation of the float expansion valve (25).

Further, it is possible to suppress the increase of the liquid surface of the liquid refrigerant caused by inhalation of the gas refrigerant in the vicinity of gas outlets (24c). Therefore, it is possible to prevent so-called liquid return that a part of the liquid refrigerant is sucked from the gas outlet (24c) to the multistage compressor (21) side.

In addition, according to the second invention, by using a small float expansion valve (25), the unit price of the float expansion valve (25) can be significantly reduced, and the number of float expansion valves (25) can be reduced to two. The cost of the entire economizer (24) can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, a two-stage turbo chiller including a two-stage turbo compressor will be described as a multistage compression refrigeration apparatus using the economizer according to the present invention.

  FIG. 1 is a piping system diagram schematically showing the configuration of a two-stage turbo chiller (1) according to an embodiment of the present invention. The two-stage turbo refrigerator (1) includes a two-stage turbo compressor (21), a condenser (22), a high-stage expansion valve (23), a low-stage expansion valve (25), and an evaporator ( 26) and a refrigerant circuit (20) for performing a vapor compression refrigeration cycle sequentially connected by refrigerant piping. An economizer (24) according to the present invention is provided between the high stage side expansion valve (23) and the low stage side expansion valve (25) of the refrigerant circuit (20).

  The two-stage turbo compressor (21) includes a low stage impeller (21a) and a high stage impeller (21b). The low stage impeller (21a) and the high stage impeller (21b) are connected in series. The two-stage turbo compressor (21) is provided with a suction capacity control mechanism (21c) for controlling the suction capacity and a discharge capacity control mechanism (21d) for controlling the discharge capacity. The low-pressure (PL) refrigerant sucked into the lower stage is compressed to the intermediate pressure (PM) by the lower stage impeller (21a) and sucked into the higher stage. The refrigerant sucked into the high stage is compressed by the high stage impeller (21b) to become a high-pressure (PH) gas refrigerant.

  The condenser (22) is a so-called shell-and-tube condenser including a shell (cylindrical copper) and a plurality of cooling pipes arranged in the shell. A high-pressure (PH) gas refrigerant compressed in the two-stage turbo compressor (21) is introduced into the shell, and the gas refrigerant is cooled by cooling water flowing in the cooling pipe. As a result, the gas refrigerant condenses outside the cooling pipe and becomes liquid and accumulates at the bottom of the shell.

  The high stage side expansion valve (23) is formed by a temperature-sensitive automatic expansion valve that controls the suction refrigerant superheat degree to be constant by adjusting the amount of pressure reduction in accordance with the suction refrigerant superheat degree. The liquid refrigerant and the gas refrigerant condensed in the condenser (22) are reduced to an intermediate pressure (PL) by the high stage side expansion valve (23) and introduced into the economizer (24).

  The economizer (24) is connected to a gas pipe (28) connected in the middle of the two-stage turbo compressor (21). In the economizer (24), the gas-liquid two-phase refrigerant is gas-liquid separated. The gas refrigerant is led to the middle of the two-stage turbo compressor (21) via the gas pipe (28), while the liquid refrigerant is led to the evaporator (26) side.

  The low-stage side expansion valve (25) includes a float expansion valve (25) whose throttle amount is adjusted according to the liquid level of the liquid refrigerant in the economizer (24), and the economizer (24 ) Is built in. Therefore, the liquid refrigerant separated from the gas and liquid by the economizer (24) is decompressed by the float expansion valve (25) when it flows out toward the evaporator (26).

  The evaporator (26) is constituted by a full liquid evaporator, and in this embodiment, is constituted by a so-called shell and tube type evaporator. In the evaporator (26), the liquid refrigerant that has been gas-liquid separated in the economizer (24) is supplied by being decompressed by the float expansion valve (25). A heat transfer tube is arranged in the shell, and water as an object to be cooled flows in the heat transfer tube. The liquid refrigerant supplied into the shell absorbs heat from the water in the heat transfer tube, evaporates, and is converted into a gas that is led to the suction side of the two-stage turbo compressor (21).

  Next, the economizer (24) according to the present invention will be described in detail.

  As shown in FIGS. 2 and 3 (a) and 3 (b), the economizer (24) is a horizontally long tank (24a) constituted by a cylindrical body portion and a closing portion that closes both ends of the body portion. It has. The tank (24a) has an introduction part (24d) for introducing the refrigerant of the refrigerant circuit (20), a liquid outlet part (24b) for guiding the internal liquid refrigerant to the evaporator (26), and an internal gas refrigerant And a gas outlet (24c) for guiding the gas to the middle of the two-stage turbo compressor (21).

  The introduction portion (24d) is formed at the center in the longitudinal direction of the tank (24a). As shown in FIG. 3A, the introduction part (24d) is configured by a cylindrical body that penetrates the inside and outside of the tank (24a), curves in the tank (24a), and opens upward.

  As shown in FIG. 2, two liquid outlet portions (24b) are provided in this embodiment. The two liquid outlet portions (24b) are formed at both ends in the longitudinal direction of the tank (24a). The liquid outlet portion (24b) is configured by a cylindrical body that penetrates the inside and outside of the tank (24a) and is curved and opened downward in the tank (24a).

  In the present embodiment, two gas outlets (24c) are provided. The two gas outlets (24c) are arranged one on each side of the introduction part (24d) in the longitudinal direction of the tank (24a). Further, the gas outlet (24c) is formed of a cylindrical body, extends from the upper side to the lower side of the tank (24a), and the tip penetrates the upper surface of the tank (24a) and opens at the upper layer in the tank (24a). .

  The float expansion valve (25) as a low-stage expansion valve built in the economizer (24) described above is attached to the inflow side end of the liquid outlet (24b). Specifically, as shown in FIG. 2, a valve body (25a) formed at the inflow side end of the liquid outlet portion (24b) made of a cylindrical body, and a float (25b) connected to the valve body (25a) ) And. When the float (25b) rises, the valve body (25a) moves in a direction to expand the flow path in the liquid outlet part (24b), and when the float (25b) descends, the flow path in the liquid outlet part (24b) It is configured to move in the direction of squeezing. With such a configuration, the float expansion valve (25) has its throttle amount reduced when the liquid level in the economizer (24) rises, and increases when the liquid level falls, and the throttle amount in the economizer (24) increases. The outflow amount of the liquid is controlled in accordance with the circulation amount of the refrigerant.

  Further, there are two types extending in the cross-sectional direction of the tank (24a) between the introduction part (24d) in the tank (24a), the two liquid outlet parts (24b), and the float expansion valve (25). Partition walls (24e, 24f). As shown in FIG. 3 (a), the two first partition walls (24e) provided on the introduction part (24d) side are formed of a substantially circular plate-like body, and a substantially T-shaped notch is formed. ing. On the other hand, the two second partition walls (24f) provided on the liquid outlet part (24b) side are formed of a plate-like body obtained by hollowing out a disk in an inverted T shape. The partition walls (24e, 24f) constitute a baffle plate according to the present invention.

  The tank (24a) is divided into three spaces by the first partition wall (24e) and the second partition wall (24f), and the introduction section (24d), the two liquid outlet sections (24b), and the float expansion valve ( 25) are arranged in different spaces. Further, as shown in FIG. 3B, when the space on the introduction part (24d) side is viewed from the space on the liquid outlet part (24b) side, most of the cross section of the tank (24a) is the first partition wall ( 24e) and the second partition wall (24f). With such a configuration, it is possible to prevent the refrigerant introduced from the introduction part (24d) from directly spraying on the float (25b) of the float expansion valve (25).

  The two gas outlets (24c) described above are disposed closer to the liquid outlet (24b) than the first partition (24e) and the second partition (24f). That is, the gas outlet part (24c) is a central part in which the introduction part (24d) is provided among the three spaces partitioned in the tank (24a) by the first partition wall (24e) and the second partition wall (24f). It is provided not in the space but in the space at both ends where the liquid outlet portion (24b) is provided. By arranging the gas outlet part (24c) in this way, it is possible to prevent the gas-liquid two-phase refrigerant introduced from the introduction part (24d) from being directly sucked into the gas outlet part (24c). Can do.

  Next, the operation of the two-stage turbo chiller (1) will be described. First, when the operation is started, the low-stage and high-stage impellers (21a, 21b) of the two-stage turbo compressor (21) rotate, and the low-pressure (in the refrigerant circuit (20) ( PL) refrigerant is inhaled. At this time, the refrigerant capacity to be sucked is adjusted by the suction capacity control mechanism (21c). Then, the low-pressure (PL) refrigerant sucked into the lower stage is compressed to the intermediate pressure (PM) by the lower stage impeller (21a) and sucked into the higher stage. The refrigerant sucked into the high stage side is compressed by the high stage impeller (21b) to become a high-pressure (PH) gas refrigerant and discharged to the refrigerant circuit (20). At this time, the refrigerant capacity discharged by the discharge capacity control mechanism (21d) is adjusted.

  The high-pressure (PH) refrigerant discharged from the two-stage turbo compressor (21) to the refrigerant circuit (20) is cooled and condensed in the condenser (22). Then, the liquid refrigerant and the gas refrigerant condensed in the condenser (22) are reduced to an intermediate pressure (PL) by the high stage side expansion valve (23) and introduced into the economizer (24). The decompression amount of the high stage side expansion valve (23) is adjusted according to the degree of superheat of the suction refrigerant. Thus, the refrigerant circulation amount is controlled so that the suction refrigerant superheat degree becomes a predetermined value.

  In the tank (24a) of the economizer (24), the introduced gas-liquid two-phase refrigerant is gas-liquid separated. The gas refrigerant after gas-liquid separation is led to the middle of the two-stage turbo compressor (21) via the gas pipe (28), while the liquid refrigerant is led to the evaporator (26) side.

  The intermediate-pressure (PM) gas refrigerant introduced to the middle of the two-stage turbo compressor (21) is mixed with the intermediate pressure (PM) compressed on the low-pressure side of the two-stage turbo compressor (21). Inhaled to the side and compressed.

  On the other hand, when the liquid refrigerant guided to the evaporator (26) flows out from the liquid outlet part (24b) toward the evaporator (26), the float expansion valve (25) provided in the liquid outlet part (24b) The pressure is reduced to a low pressure (PL) by the pressure and supplied to the evaporator (26).

  The low-pressure (PL) refrigerant thus depressurized by the float expansion valve (25) and supplied to the evaporator (26) absorbs heat from the water in the heat transfer pipe and evaporates to become a gas, which is a two-stage turbocharger. Guided to the suction side of the compressor (21). The gas refrigerant is sucked into the two-stage turbo compressor (21) and compressed.

  Next, the operation of the economizer (24) will be described in detail.

  The refrigerant introduced into the central space in the longitudinal direction in the tank (24a) through the introduction part (24d) diffuses from the central space in the longitudinal direction in the tank (24a) to the spaces on both ends. At this time, the refrigerant collides with both the partition walls (24e, 24f) and the inner wall surface of the tank (24a), whereby the gas and liquid are separated. Then, the separated liquid refrigerant flows down along both the partition walls (24e, 24f) and the inner wall surface of the tank (24a), and accumulates at the bottom of the tank (24a). On the other hand, the gas refrigerant flows from the gap between the both partition walls (24e, 24f) and the inner wall surface of the tank (24a) to the space on the liquid outlet part (24b) side.

  Then, in the space on the liquid outlet part (24b) side in the tank (24a), the liquid refrigerant flows from the liquid outlet part (24b) to the evaporator (26) side. At this time, the flow path formed in the liquid outlet part (24b) is throttled by the valve body (25a) of the float expansion valve (25). Therefore, the liquid refrigerant is decompressed by the float expansion valve (25).

  The float expansion valve (25) is configured such that its throttle amount is adjusted according to the liquid level of the liquid refrigerant in the tank (24a). Therefore, when the liquid level rises, the float (25b) rises, and the valve body (25a) moves in a direction in which the flow path in the liquid outlet part (24b) further expands. As a result, the throttle amount decreases, the amount of liquid refrigerant flowing out increases, and the rising speed of the liquid level slows down or starts to descend. On the other hand, when the liquid level is lowered, the float (25b) is lowered, and the valve body (25a) moves in a direction to further restrict the flow path of the liquid outlet part (24b). As a result, the throttle amount increases, the outflow amount of the liquid refrigerant decreases, and the descending speed of the liquid level becomes slow or starts to rise. In this manner, the liquid level height of the liquid refrigerant in the tank (24a) is controlled by the float expansion valve (25) so as to realize a throttle amount corresponding to the refrigerant circulation amount.

  On the other hand, in the space on the liquid outlet (24b) side, the gas refrigerant is sucked from the gas outlet (24c) to the intermediate pressure side of the two-stage turbo compressor (21). In the present embodiment, since two gas outlet portions (24c) are provided, gas refrigerant is not intensively sucked from one gas outlet portion (24c), but two gas outlet portions ( 24c) is dispersed and inhaled. Therefore, when the gas refrigerant is sucked, the pressure in the vicinity of the gas outlet part (24c) is lower than the other part in the tank (24a), but compared with the case where there is only one gas outlet part (24c), The degree of low pressure can be reduced. Therefore, even if the liquid refrigerant is sucked and raised to the gas outlet part (24c) side below the gas outlet part (24c), the rising height can be suppressed. As a result, it is possible to suppress the liquid refrigerant from being sucked into the gas outlet (24c) together with the gas refrigerant.

-Effect of the embodiment-
As described above, according to the economizer (24) according to the present embodiment, the liquid outlet portion (24b) and the float expansion valve (25), which are conventionally provided only one, are provided two by two. Therefore, liquid refrigerant flows out from the tank (24a) through the two liquid outlet portions (24b), and the outflow amount of the liquid refrigerant is controlled by the two float expansion valves (25). Become. Thereby, the control amount calculated | required by each float expansion valve (25) becomes small compared with the case where the outflow amount is controlled by one float expansion valve (25). Therefore, according to this economizer (24), a small float expansion valve (25) can be used, and the unit price of the float expansion valve (25) can be significantly reduced. Therefore, the cost of the entire economizer (24) can be reduced.

  Moreover, according to this economizer (24), two float expansion valves (25) are provided. Therefore, even if one float expansion valve (25) stops operating due to a malfunction, the pressure reduction of the liquid refrigerant and the liquid level control in the economizer (24) can be performed by the other float expansion valve (25). Therefore, according to the present economizer (24), even when a malfunction occurs in the float expansion valve (25), a multistage compression refrigeration apparatus (in this embodiment, a two-stage turbo refrigeration apparatus) provided with the economizer (24). The operation can be continued by partial load operation or the like without immediately stopping the operation of the refrigerator (1)).

  In this embodiment, the number of the liquid outlet part (24b) and the float expansion valve (25) is two, but three or more liquid outlet parts (24b) and the float expansion valve (25) may be provided. Good. Even in that case, the float expansion valve (25) can be reduced in size, and the economizer (24) can be configured at low cost. On the other hand, in this embodiment, the number of float expansion valves (25) is set to two, so that the size of the float expansion valve (25) can be reduced, the unit price can be greatly reduced, and the cost of the entire economizer (24) can be reduced. Can be further reduced.

  Moreover, according to this economizer (24), each float expansion valve (25) is arrange | positioned at the both sides of the introducing | transducing part (24d) in the longitudinal direction of the tank (24a). Therefore, each float expansion valve (25) is arranged at an interval from the introduction portion (24d). Thereby, it can be avoided that the refrigerant introduced from the introduction part (24d) is sprayed on the float (25b) of the float expansion valve (25). Therefore, it is possible to prevent the introduced refrigerant from affecting the operation of the float expansion valve (25).

  Moreover, according to this economizer (24), it extends in the cross-sectional direction of the tank (24a) between each of the introduction part (24d), the two liquid outlet parts (24b), and the float expansion valve (25). A partition wall (24e, 24f) made of a plate-like body is provided. Thereby, the gas-liquid two-phase gas-liquid is separated, and the refrigerant introduced from the introduction part (24d) directly blows on the float (25b) of the float expansion valve (25) to float the float expansion valve (25). It is possible to prevent the operation from being affected.

  By the way, when the gas refrigerant is sucked from the gas outlet (24c), the vicinity of the gas outlet (24c) has a lower pressure than the surroundings. Therefore, when only one gas outlet (24c) is provided, the pressure difference between the vicinity of the gas outlet (24c) and the surroundings becomes large, and the liquid refrigerant level in the tank (24a) becomes the gas outlet. (24c) It will rise greatly in the vicinity. For this reason, there is a risk of so-called liquid return in which part of the liquid refrigerant is sucked into the two-stage compressor (21) from the gas outlet (24c).

  However, according to the present economizer (24), two gas outlets (24c) are provided, one on each side of the introduction part (24d) in the longitudinal direction of the tank (24a). As a result, the gas refrigerant is not intensively sucked from one gas outlet (24c), but is distributed and sucked into two gas outlets (24c). Therefore, compared with the case where only one gas outlet part (24c) is provided, the force at which each gas outlet part (24c) sucks the gas refrigerant is halved. Thereby, it is possible to suppress an increase in the liquid refrigerant level caused by the suction of the gas refrigerant in the vicinity of the gas outlet (24c). As a result, it is possible to avoid so-called liquid return in which a part of the liquid refrigerant is sucked into the two-stage turbo compressor (21) from the gas outlet (24c).

<< Other Embodiments >>
In the above embodiment, the number of the liquid outlet part (24b) and the float expansion valve (25) is two, but three or more liquid outlet parts (24b) and the float expansion valve (25) may be provided. Even in that case, the float expansion valve (25) can be reduced in size, and the economizer (24) can be configured at low cost.

  Moreover, in the said embodiment, although the introducing | transducing part (24d), the liquid outlet part (24b), and the gas outlet part (24c) were formed with the cylindrical body, you may form these by a mere opening.

  Furthermore, in the above-described embodiment, the two-stage compression / two-expansion refrigeration apparatus has been described as the multistage compression refrigeration apparatus including the economizer (24) according to the present invention. You may apply to a multistage compression refrigerating apparatus. At that time, a plurality of the economizers are arranged in series.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for a turbo refrigerator.

It is a piping system diagram showing a schematic configuration of a multistage turbo refrigerator according to an embodiment. It is a longitudinal cross-sectional view of an economizer. (A) is the IIIa-IIIa sectional view taken on the line of FIG. 2, (b) is the IIIb-IIIb sectional view of FIG.

1 Two-stage turbo refrigerator (multistage compression refrigeration system)
20 Refrigerant circuit 21 Two-stage turbo compressor (multistage compressor)
22 Condenser 23 High-stage expansion valve (multi-stage expansion means)
24 economizer 24a tank 24b liquid outlet 24c gas outlet 24d inlet 24e first partition (baffle plate)
24f 2nd partition wall (binder plate)
25 Float expansion valve (multi-stage expansion means)
25a Valve body 25b Float 26 Evaporator 28 Gas piping

Claims (5)

A multistage compression refrigeration system (20) having a refrigerant circuit (20) in which a multistage compressor (21), a condenser (22), a multistage expansion means (23, 25), and an evaporator (26) are sequentially connected ( An economizer provided in 1) for gas-liquid separation of a gas-liquid two-phase refrigerant, guiding gas refrigerant to the middle of the multistage compressor (21) and guiding liquid refrigerant to the evaporator (26);
Between the introduction part (24d) for introducing the refrigerant of the refrigerant circuit (20), the liquid outlet part (24b) for leading the liquid refrigerant to the evaporator (26), and the multistage compressor (21) A tank (24a) formed with a gas outlet (24c) for introducing a gas refrigerant;
An expansion valve that constitutes a part of the multistage expansion means (23, 25), is attached to the liquid outlet (24b), and is throttled according to the liquid level of the liquid refrigerant in the tank (24a) A float expansion valve (25) whose amount is adjusted,
An economizer comprising a plurality of the liquid outlet (24b) and the float expansion valve (25). In claim 1,
An economizer characterized in that the liquid outlet part (24b) and the float expansion valve (25) are provided two by two. In claim 2,
The tank (24a) is a horizontally long tank,
The introduction part (24d) is formed in the central part in the longitudinal direction of the tank (24a),
The economizer according to claim 1, wherein the liquid outlet part (24b) and the float expansion valve (25) are arranged one on each side of the introduction part (24d) in the longitudinal direction of the tank (24a). In claim 3,
Between each of the introduction part (24d), the two liquid outlet parts (24b) and the float expansion valve (25), there are baffle plates (24e, 24f) extending in the cross-sectional direction of the tank (24a). An economizer characterized by being provided. In claim 4,
Two gas outlets (24c) are provided, and are arranged on the liquid outlet part (24b) side of the baffle plates (24e, 24f) in the longitudinal direction of the tank (24a), respectively. An economizer.

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